In recent years a development of new types of chemical power sources is under way all over the world. Batteries with mechanical recharge, in which the active mass is replaced upon being consummed are now possible. These types of batteries are either being actively developed or being readied for mass production. They are: aluminum-air, lithium-air and zinc-air batteries. Other metals could also be used as active anodic components (magnesium, iron etc.) Such batteries usually consist of a larger number of cells connected in series for increasing the voltage of the source. In such a case the problem of establishing a good electric contact between the anode of one cell and the cathode of the adjacent cell is encountered. All the current drained from the battery is transmitted from the anode plate of one cell onto the adjacent cathode through this connection.
The larger the plate dimensions and hence the current drain, the larger are also losses occuring in that connection.
In other electrochemical systems (large industrial electrolyzers) this problem is solved by introduction of the so-called bipolar electrodes, i.e. electordes whose one side serves as an anode and the other side as a cathode of the adjacent cell. In this way exeptional simplicity of construction is achieved; there is no need for external connections and the electric resistance is made negligibly small.
This principle has so far not been used in chemical power sources with mechanical recharging. The problem of achieving bipolar electrode construction in this system is more complex than in other systems because the two electrodes have a completely different character. One is being consummed during the operation of the battery, which the other must be continuously supplied with an electochemically active substance (e.g. oxygen from the air). This is the probable reason why the bipolar electrode principle has not yet been applied to these systems.